Amantadine and motor fluctuations in chronic Parkinson's disease.

Twenty patients with idiopathic Parkinson's disease (PD) and motor fluctuations received open-label amantadine (100-200 mg/d) in addition to their other antiparkinson medications. One patient had unpredictable motor fluctuations (on-off) and the others had end-of-dose wearing-off. The effect of amantadine on motor fluctuations and parkinsonian disability was tested at 1, 2, and 3 months. Moderate improvement in motor fluctuations occurred in 55% of the patients at 2 months and 65% of patients at 3 months of treatment (p less than 0.01). There was also significant improvement in parkinsonian disability. The duration of improvement averaged 5.7 months, and all patients deteriorated to their baseline level of function within 12 months. This study suggests that the addition of amantadine can transiently improve motor fluctuations and have a significant impact on overall disability in patients with chronic PD.